Flat wiper blade

ABSTRACT

Flat wiper blade for windscreen wiper modules, having a wiper blade body, which presents at least one wiping rubber ( 12 ) forming at least one wiping lip ( 12.1 ), presents at least one spring rail ( 11 ) in addition to at least one retaining strip ( 10 ) on which the wiping rubber ( 12 ) is held and which (retaining strip ( 10 )) possesses at least one profile section designed as a hollow profile, in which at least a partial length of the spring rail ( 11 ) is accommodated, wherein at least one heating foil ( 19 ) is arranged over at least a partial length together with the at least one spring rail ( 11 ) in the profile section ( 10.1 ) of the retaining strip ( 10 ).

The invention refers to a flat wiper blade according to the generic termof patent claim 1.

Flat wiper blades, which essentially consist respectively of at leastone spring rail, a wiping rubber connected to the spring rail andforming at least one wiping lip, in addition to a wiper blade adapter,with which the respective wiper blade can be detachably mounted on awiper arm and on an adapter on the wiper arm side at this position, arealso known in particular in various different embodiments for windscreenwiper modules of road vehicles.

Also known in this case are electrically heatable flat wiper blades (DE102 34 267 A1), which present at least one electric heating elementcomposed of a heating filament or a heating foil, which is subsequentlycovered towards the outside for instance by a spoiler profile held onthe upper side of the wiper blade by locking or however arranged in arecess of the wiping rubber by the spring rail connected to the wipingrubber. It is disadvantageous among other aspects that these known wiperblades are elaborate in terms of design and production engineering andalso that the heat transfer from the respective heating element to theareas of the wiper blade to be heated is ineffective and indeedparticularly when heat transfer is performed via the wiping rubber.

In addition, flat wiper blades are known (DE 100 39 290 A1), in whichtwo of electric heating elements each composed of a heating foil arearranged on the underside of the wiper blade exposed on both sides ofthe tilting web and therefore not protected against environmentalinfluences. Furthermore, in this case also, heat is again transferredineffectively via the respective wiping rubber.

Also known furthermore are electrically heatable wiper blades designedas bow wiper blades having respectively one wiping rubber and two springrails accommodated in longitudinal grooves of the wiping rubber (U.S.Pat. No. 6,591,443 B1). Heating foils serve as heating elements and arelikewise accommodated in the longitudinal grooves of the wiping rubber.It is disadvantageous among other aspects that the electrical connectionof the heating foils to an external electrical supply lead is performedvia a plug connection and a double plug connector, the contacts of whichengage in sockets embedded in the wiping rubber. Apart from the factthat this known wiper blade does not involve a flat wiper blade and thatowing to the nature of the electrical connection, it does not fulfil thecurrent quality requirements and is also extremely susceptible tofaults, these known wiper blades also present the disadvantage that theheating elements and heating foils are arranged to the greatest extentunprotected. The nature of the electrical connection of the heatingelements in turn requires elaborate manufacture of the respective wipingrubber.

The purpose of the invention is to demonstrate a wiper blade that avoidsthe above-mentioned disadvantages and which with the possibility ofrational production, ensures optimum heat transfer from the at least oneheating foil to the wiper blade and to the latter's areas to be heated,in addition to an arrangement of the heating foil which is protectedagainst external influences. In order to solve this problem, a wiperblade according to patent claim 1 is developed.

Further developments, advantages and application possibilities of theinvention are also apparent from the following description of examplesof embodiment and from the figures. In this case, all thecharacteristics described and/or illustrated are in themselves or in anydesired combination fundamentally a subject of the invention, regardlessof their summary in the claims or their backward relation. The contentsof the claims are also made an integral part of the description.

The invention is described below in further detail in examples ofembodiment based on the figures:

FIG. 1 shows a simplified representation of a wiper arm together with awiper blade provided on this wiper arm and in contact with a vehiclewindscreen;

FIG. 2 shows a perspective individual representation of the wiper bladein FIG. 1 together with a wiper blade adapter, shortly before finalinstallation of this adapter on the wiper blade;

FIG. 3 shows a perspective representation of a retaining strip of thewiper blade in FIGS. 1 and 2, together with a heating foil, a springrail and a wiping rubber;

FIGS. 4 and 5 show sections through the arrangement in FIG. 3 in thearea of the sectional planes I-I and II-II;

FIG. 6 shows an enlarged perspective individual representation of thearrangement in FIG. 3 in the centre of the wiper blade;

FIG. 7 shows a partial representation of a longitudinal section throughthe arrangement in FIG. 3 with the wiper blade adapter installed;

FIG. 8 shows a schematic representation of a top view of the spring railwith the heating foil;

FIG. 9 shows a section along the line III-III in FIG. 8;

FIG. 10 shows a representation similar to that in FIG. 6 with a furtherform of embodiment;

FIG. 11 shows a partial representation of a longitudinal section throughthe arrangement in FIG. 10.

FIG. 1 illustrates a wiper arm 1 together with a wiper blade 3detachably mounted on this wiper arm and in contact with a vehiclewindscreen 2 which is executed as a flat wiper blade or a flatwiper-blade in the manner described in further detail below.

The wiper arm 1 is designed in the usual manner, i.e. consisting of abearing section 4 for attachment to a wiper shaft, not illustrated, ofthe vehicle windscreen wiper module, an articulation piece 5, which isconnected to the bearing section 4 by means of a wiper arm articulation6 and a wiper rod 7, connected to the articulation piece 5, carrying onits free end an adapter 8 on the wiper arm side. By means of thisadapter 8, the wiper blade 3 is detachably connected to the wiper arm 1in the manner described below mechanically by means of an adapter orwiper blade adapter 9 on the wiper blade side and also hydraulically inthe form of embodiment presented.

The wiper blade 3 is executed as an electrically heated wiper blade andindeed in the embodiment presented also as a wet wiper blade, by meansof which controlled application of a washing or cleaning fluid (waterwith cleaning and/or antifreeze additives if required) to the vehiclescreen 2 is also additionally possible.

As can be gathered from FIGS. 3-7 in particular, the wiper blade 3comprises among other aspects a profile or retaining strip 10,preferably manufactured from plastic, which extends over the entire oralmost entire length of the wiper blade 3 and which accommodates in aprofile section 10.1 designed as a hollow profile a flat spring rail 11manufactured from spring steel, which likewise extends over the entirelength of the wiper blade 3 and which has sections 11.1 projecting fromthe retaining strip 10 at both wiper blade ends. In order to avoidimpairment of the necessary flexibility of the wiper blade 3 by theretaining strip 10, the latter is provided with a large number ofnotches 10.2 on its hollow profile section receiving the spring rail 11.In order to allow attachment of the wiper blade adapter 9 to the springrail 11, the retaining strip 10 is also laterally open on its profilesection 10.1 receiving the spring rail, so that the spring rail 11 isexposed at this position with peripheries 11.2 for attachment of thewiper blade adapter 9.

The wiper blade furthermore comprises a wiping rubber 12 consisting ofrubbery-elastic profile material, which among other aspects forms thewiping lip 12.1 in contact with the vehicle windscreen 2 and which isheld with a positive fit in the retaining strip with a profile section12.2. On both sides of the wiper blade adapter 9 attached to theretaining strip 10 and to the spring rail 11 in the centre orapproximately in the centre of the wiper blade 3 and spanning theretaining strip 10 in addition to the spring rail 11 on its upper sidefacing away from the wiping lip 12.1 in the manner of slide, a spoilerprofile 13 respectively is fixed to the retaining strip. Each spoilerprofile 13, which starting from the wiper blade adapter 9 extends almostto one end of the wiper blade 3, is executed with two injection ducts 14in the way known to the person skilled in the art, of which oneinjection duct 14 of a spoiler profile 13 on one longitudinal side of awiper blade is schematically implied in FIG. 2. The injection ducts 14are respectively designed in the manner known to the person skilled inthe art with a large number of jet openings for application of thewashing and cleaning fluid supplied to the respective duct 14 to thevehicle windscreen, as implied by 15 in FIG. 15. The injection ducts 14are each connected to a connection nozzle 16, which is executed forexample in one piece with the wiper blade adapter 9 manufactured as aplastic moulding. Both connection nozzles 16 on the longitudinal sidesof the wiper blade adapter 9 and the wiper blade 3 respectively form acommon connection duct, which is linked to a hydraulic and fluidconnection 17 and to be more precise, for respective connection of aflexible supply or hose line not illustrated running along the wiper armfor delivery of the washing and cleaning fluid to the injection ducts14.

At both ends, the wiper blade 3 is closed respectively by an end cap 18manufactured as a plastic moulding, which is held in place by snappingon to the section 11.1 of the spring rail 1.

An electric heating foil 19 is arranged on the upper side of the springrail 11 facing the top side of the wiper blade. According to FIGS. 8 and9, this heating foil 19, which extends over the entire length orsubstantially over the entire length of the spring rail 11 accommodatedin the profile section 10.1 of the retaining strip 10, is composed forexample of a single-layer or multiple-layer foil made of an electricallyinsulating material, e.g. a carrier layer or insulating layer 20manufactured from plastic and of a metallisation 21 applied to thisinsulating layer 20, which (metallisation) is located on the surfaceside of the insulating layer 20 facing away from the spring rail 11 andis at least executed and/or structured such that it forms at least oneheating conductor 21.1 extending over the entire length or substantiallythe entire length of the heating foil 19. With its surface side notpresenting the metallisation 21, the heating foil 19 is in contact withthe top side, i.e. the upper side of the spring rail 11 facing away fromthe wiping lip 12.1. The metallisation 21 is fixed in a suitable way tothe insulating layer 20, for instance by gluing or in anotherappropriate manner and consists for example of a correspondinglystructured metal foil and/or of an electric heating filament etc. In theembodiment presented, the metallisation 21 is structured in such a wayas to form a single heating conductor 21.1, which extends starting fromthe central section of the spring rail 11 and the heating foil 19 at theone end, from this point back to the other end of the heating foil 19and subsequently back to the central area of the heating foil 19. Atboth ends of the heating conductor 21.1, the latter and themetallisation 21 are designed with an electrical connection or contactarea 22 to which the conductor of a flexible electric lead isrespectively connected. The electrical connection 24 of the heating foil19 composed of the two contact areas 22 in the centre or approximatelyin the centre of the wiper blade 3 is covered in the form of embodimentpresented by electrical insulation 25, which is produced for example bymoulding and from which the two flexible leads 23 are brought out.

At their other ends, the leads 23 are each equipped with anon-illustrated plug connector and to be more precise, for connection toan electrical supply lead, a partial length of which runs among otheraspects along the wiper arm 1 and to a connection (mating connector) ofthis electrical supply lead provided for example in the adapter 8.

As can be gathered from FIGS. 3-7, the heating foil 19 runs in the areaof the centre of the wiper blade in the case of the wiper blade 3, i.e.where the adapter 9 is also provided, with a partial length 19.1 on theupper side of the retaining strip 10 facing away from the wiping lip12.1, i.e., outside the profile section 10.1, whereas otherwise, theheating foil 19 is accommodated directly in contact with the spring rail11 within the profile section 10.1 of the retaining strip 10. Theheating foil 19 runs through two notches for this purpose.

The electrical connection 24 is provided on the partial length 19.1.After fitting of the wiper blade adapter 9, the electrical connection 24is located under the wiper blade adapter, so that both the electricalconnection and the partial length 19.1 are covered by the installedwiper blade adapter 9.

Both electrical connecting leads 23 extend starting from the electricalconnection 24 under the wiper blade adapter 9, through, i.e. between thelatter and the partial length and are brought out on the front side 9.1of the wiper blade adapter 9 on which the two fluid connections 17 areprovided.

Installation of the wiper blade 3 is performed for example such that theheating foil 19 is initially inserted into the retaining strip 10 and tobe more precise with both its ends ahead of the centre of the retainingstrip 10. In so doing, the heating foil 19 is preferably provided withthe electrical leads 23 and the insulation 25. Subsequently, the springrail 11 is pushed into the retaining strip 10. During this installation,alignment of the heating foil is possible by means of longitudinaldisplacement, particularly also in such a way that the electricalconnection 24, after alignment, is located in the position where thewiper blade adapter 9 is subsequently installed. Owing to the specificcourse of the heating foil 19 over the partial length 19.1 outside theretaining strip 10 and otherwise within this retaining strip, althoughthe alignment and axial displacement of the heating foil is admittedlyrendered more difficult, it is hereby guaranteed however thatdisplacement or excessive displacement of the aligned heating foil 19does not occur on installation of the spring rail 11. The describedembodiment of the wiper blade 3 has several advantages:

-   -   owing to the arrangement of the heating foil on the spring rail        11 composed of metallic material, a distribution of the electric        heating output over the entire wiper blade length that is at        least uniform to the greatest extent is fundamentally achieved        and consequently uniform heating of the wiper blade,        particularly also of the wiping rubber 12 and of the injection        ducts 14.    -   With a simplified construction and simplified production, the        heating foil 19 is accommodated within the retaining strip 10        protected against external influences, particularly also against        external mechanical influences.    -   Owing to the course of the heating foil 19 over the partial        length 19.1 on the upper side of the retaining strip, improved        heating of the wiper blade adapter and the fluid ducts designed        in this adapter is achieved.    -   Optimum heat input results via the spring rail 11.    -   Through the electrical leads 23, which incidentally may also be        grouped together to form a single, at least bifilar flexible        lead, an electrical connection with the electrical supply lead        running on the wiper arm 1 that is reliable and detachable at        any time on changing the wiper blade is possible.

FIGS. 10 and 11 show the retaining profile 10 with the spring rail 11and with the heating foil 19 in a further form of embodiment that solelydiffers from the form of embodiment previously described in that theheating foil 19 is also in contact with the upper side of the springrail 11 in the area of the wiper blade adapter 9 and in the area of theelectrical connection 24 at this position, i.e. does not present thepartial length 19.1 running on the upper side of the retaining strip.The retaining strip 10 is designed with an opening 27 in the area of thecentre of the wiper blade, i.e. where the electrical connection 24 isprovided, in which the connection 24 and the insulation 25 are at leastpartially accommodated and out of which the electrical leads 23 arebrought out. The opening 27 is of sufficiently large diameter in thelongitudinal direction of the wiper blade so that once again, alignmentof the heating foil 19 by longitudinal displacement is possible.Installation of the wiper blade 3 is likewise preferably performed insuch a way that the heating foil 19 is initially inserted into theprofile section of the retaining strip 10, is then aligned in thelongitudinal direction of the retaining strip 10 and subsequently thespring rail 11 is installed; though also after installation of thespring rail 11, alignment of the heating foil 19 is possible bylongitudinal displacement.

The invention has been described above based on examples of embodiment.It is understood that numerous modifications and variations are possiblewithout departing as a result from the concept on which the invention isbased.

It was therefore assumed above that the wiper blade presents only onespring rail 11, which is accommodated in the retaining strip 10. Inprinciple however, the possibility also exists of making provision forseveral spring rails and/or several heating foils, with at least onespring rail being accommodated in a hollow profile of the retainingstrip in this case and to be more precise, together with at least oneheating foil.

Especially with the form of embodiment described in connection withFIGS. 10 and 11, the possibility exists of pre-installing the at leastone heating foil on the spring rail 11, for instance by gluing, e.g.with a heat-transfer adhesive and subsequently of introducing ittogether with the rail 11 into the retaining strip 10. The electricalconnection with the leads 23 is then performed after installation of thespring rail 11 and the heating foil 19.

It was assumed above that the metallisation 21 forms a single continuousheating conductor 21.1 or heating circuit. Other embodiments are ofcourse also possible, for example such that the metallisation 21 formstwo or however more than two heating conductors 21.1 or heating circuitsthat are electrically parallel and respectively connected to the contactareas 22.

It was furthermore assumed above that the metallisation 21 and the atleast one heating conductor 21.1 consisting of this metallisation isprovided by gluing or another means on the electrically insulating layer20. The metallisation may of course also be created in another way, forexample by vapour deposit of an electrically conductive material, forexample a metal and/or by electrolytic and/or chemical deposit and/or byspattering etc.

It was also assumed above that the heating foil 19 consists of theinsulating layer 20 and the metallisation 21 provided on a surface sideof this insulating layer. It is also basically possible that on thesurface side of the insulating layer 20 presenting the metallisation 21,a covering layer concealing and protecting the metallisation 21 isapplied, as implied by the broken lines 27 in FIG. 9.

LIST OF REFERENCES

-   1 wiper arm-   2 vehicle windscreen-   3 wiper blade-   4 bearing section-   5 articulation piece-   6 wiper arm articulation-   7 wiper rod-   8 adapter on wiper arm side-   9 wiper blade adapter-   9.1 front side of wiper blade adapter-   10 retaining strip-   10.1 notch-   11 spring rail-   11.1 section of spring rail 11-   11.2 periphery-   12 wiping rubber-   12.1 wiping lip-   12.2 profile section-   13 spoiler profile-   14 injection duct-   15 jet opening-   16 connection nozzle-   17 fluid connection-   18 end cap-   19 heating foil-   19.1 partial length of the heating foil-   20 insulating layer-   21 metallisation-   21.1 heating conductor-   22 contact area-   23 flexible electrical lead-   24 electrical connection-   25 insulation-   26 opening-   27 covering layer

The invention claimed is:
 1. A flat wiper blade for windscreen wipermodules, comprising: a wiper blade body, which presents a wiping rubberforming a wiping lip; a spring rail; a retaining strip configured toretain the wiping rubber, the retaining strip possesses a profilesection executed as a hollow profile that is laterally closed away froma center of the retaining strip, in which a partial length of the springrail and a heating foil are accommodated, wherein the heating foil isabove both the spring rail and the wiper blade, wherein, in a centralarea of the wiper blade, an electrical connection for the heating foilis provided, wherein the electrical connection is covered by a wiperblade adapter, wherein in the central area of the retaining strip, theretaining strip is laterally open on a profile section near the centerof the retaining strip and adapted to expose the spring rail forattachment of the wiper blade adapter, wherein the spring rail comprisessections projecting over the retaining strip, and wherein at both ends,the wiper blade is closed by an end ca covering each section of thespring rail.
 2. The flat wiper blade according to claim 1, wherein asurface side of the heating foil is in contact with a surface side ofthe spring rail and/or is connected to the spring rail.
 3. The flatwiper blade according to claim 1, wherein the heating foil isaccommodated over its entire length in the profile section of theretaining strip.
 4. The flat wiper blade according to claim 1, wherein apartial length of the heating foil is brought out in a central area ofthe wiper blade from the profile section of the retaining strip or isprovided running on the upper side of the retaining strip facing awayfrom the wiping lip.
 5. The flat wiper blade according to claim 1,wherein the electrical connection is composed of two contact surfaces ofthe heating foil connected to conductors of a flexible lead covered byelectrical insulation.
 6. The flat wiper blade according to claim 1,wherein the end cap is held in place by snapping onto the section of thespring rail.
 7. A flat wiper blade for windscreen wiper modules,comprising: a wiper blade body, which presents a wiping rubber forming awiping lip; a spring rail; a retaining strip configured to retain thewiping rubber, the retaining strip possesses a profile section executedas a hollow profile that is laterally closed, in which a partial lengthof the spring rail and a heating foil are accommodated, wherein theheating foil is above both the spring rail and the wiper blade, whereinthe heating foil comprises an insulating layer bearing a heatingconductor, wherein the heating foil is a thin sheet and the heatingconductor is located on the surface side of the insulating layer facingaway from the spring rail, wherein the spring rail comprises sectionsprojecting over the retaining strip, and wherein at both ends, the wiperblade is closed by an end cap covering each section of the spring rail.8. The flat wiper blade according to claim 7, wherein the insulatinglayer is in contact against the spring rail with a surface side facingaway from the heating conductor or is connected to the spring rail overa partial length.
 9. The flat wiper blade according to claim 7, whereinthe heating conductor is composed of a metallisation on the insulatinglayer comprising one of a structured metal foil or an electric heatingfilament.
 10. A flat wiper blade for windscreen wiper modules,comprising: a wiper blade body, which presents a wiping rubber forming awiping lip; a spring rail; a retaining strip configured to retain thewiping rubber, the retaining strip possesses a profile section executedas a hollow profile that is laterally closed away from a center of theretaining strip, in which a partial length of the spring rail and aheating foil are accommodated, wherein the heating foil is above boththe spring rail and the wiper blade, wherein, in a central area of thewiper blade, an electrical connection for the heating foil is provided,wherein the electrical connection is covered by a wiper blade adapter,wherein in the central area of the retaining strip, the retaining stripis laterally open on a profile section near the center of the retainingstrip and adapted to expose the spring rail for attachment of the wiperblade adapter, wherein the spring rail comprises sections projectingover the retaining strip, wherein at both ends, the wiper blade isclosed by an end cap covering each section of the spring rail, andwherein the retaining strip comprises notches on the hollow profilesection accommodating the spring rail.